He’s not alone. Other Republicans rumored to be mulling a presidential bid have also advocated increased military activity against the group, whose conquests have created a humanitarian disaster and prompted the first U.S. military intervention in Iraq in three years. Here’s a look at what they’ve said about the group, the Obama administration’s response and how the U.S. should retaliate.

Marco Rubio

In a Time op-ed earlier this month, Florida Sen. Marco Rubio, like Mr. Perry, criticized the Obama administration’s limited action against Islamic State, saying President Barack Obama‘s lack of “decisive action” in Syria allowed the group’s threat to expand beyond the country’s borders.

Sen. Marco Rubio

AFP/Getty Images

Mr. Rubio called for the U.S. to launch further airstrikes on supply routes from Syria, the group’s leadership and frontline military units, among other targets. He also advocated upping U.S. military and humanitarian aid to the Iraqi government and Kurdistan Regional Government.

Like Mr. Perry, the Florida senator warned that the U.S. could face attacks on its own territory or against American citizens if steps aren’t taken against Islamic State. His op-ed was penned before the group released a video Tuesday that showed the murder of American journalist James Foley.

“We have seen time and again in recent decades that terrorist groups, once established, use safe havens to launch attacks on the United States and our interests,” Mr. Rubio wrote. “We ignore this history at our own peril.”

Ted Cruz

Texas Sen. Ted Cruz, also considered a likely presidential contender, has offered a harsh assessment of Islamic State but has shied away from delivering any specific policy recommendations. Calling the Islamic State “the face of evil” while speaking to reporters after the Family Leadership Summit in Iowa earlier this month, Mr. Cruz said lawmakers should pressure the administration to outline its military objective—”rather than doing an airstrike here and a missile drop there that is not directed to accomplishing quantifiable military objectives that further our national security interests.”

Sen. Ted Cruz

Associated Press

Mr. Cruz blamed the “Obama-Clinton foreign policy” for the growing threat in the Middle East. “For the last five years, America has receded from leadership in the world, and that has created a vacuum,” he said.

Should the Obama administration wish to continue its strikes against the group, the president must seek congressional authorization, he added.

Rand Paul

Least talkative about what role the U.S. should play in taking down Islamic State has been Kentucky Sen. Rand Paul, whose foreign policy has frequently come under fire for veering into isolationist waters.

In June, he wrote an op-ed in the Journal arguing against U.S. military intervention in Iraq. But last month, he engaged in a debatewith Mr. Perry after the Texas governor wrote a Washington Post op-ed saying it was “disheartening” to hear Republicans, including Mr. Paul, suggest the U.S. “ignore” the turmoil in Iraq. In a Politico op-ed, Mr. Paul fired back: “Governor Perry writes a fictionalized account of my foreign policy so mischaracterizing my views that I wonder if he’s even really read any of my policy papers.”

Sen. Rand Paul

AP

In the column, Mr. Paul said he supported continuing aid to the Iraqi government and “using advanced technology to prevent ISIS from becoming a threat.” But he argued against sending U.S. troops back to Iraq, writing: “After a decade of the United States training the (sic) Iraq’s military, when confronted by the enemy, the Iraqis dropped their weapons, shed their uniforms and hid. Our soldiers’ hard work and sacrifice should be worth more than that. Our military is too good for that.”

About Washington Wire

Washington Wire is one of the oldest standing features in American journalism. Since the Wire launched on Sept. 20, 1940, the Journal has offered readers an informal look at the capital. Now online, the Wire provides a succession of glimpses at what’s happening behind hot stories and warnings of what to watch for in the days ahead. The Wire is led by Reid J. Epstein, with contributions from the rest of the bureau. Washington Wire now also includes Think Tank, our home for outside analysis from policy and political thinkers.